Method of making a polymer ammunition cartridge having a metal injection molded primer insert

ABSTRACT

The present invention provides a method of making a polymer ammunition cartridge having a metal injection molded primer insert.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of U.S. application Ser. No. 14/011,202 entitled “Lightweight Polymer Ammunition Cartridge Casings” filed on Aug. 27, 2013, which is a Divisional of U.S. patent application Ser. No. 13/292,843 entitled “Lightweight Polymer Ammunition Cartridge Casings” filed on Nov. 9, 2011 which issued as U.S. Pat. No. 8,561,543 on Oct. 22, 2013, which claims priority to U.S. Provisional Application Ser. No. 61/456,664 entitled “Polymer Case Ammunition and Methods of Manufacturing the Same (diffuser and exacter insert)” filed on Nov. 10, 2010. The contents of which are incorporated by reference in their entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of ammunition, specifically to compositions of matter and methods of making and using substantially cylindrical inserts made by metal injection molding.

STATEMENT OF FEDERALLY FUNDED RESEARCH

None.

INCORPORATION-BY-REFERENCE OF MATERIALS FILED ON COMPACT DISC

None.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is described in connection with lightweight polymer cartridge casing ammunition. Conventional ammunition cartridge casings for rifles and machine guns, as well as larger caliber weapons, are made from brass, which is heavy, expensive, and potentially hazardous. There exists a need for an affordable lighter weight replacement for brass ammunition cartridge cases that can increase mission performance and operational capabilities. Lightweight polymer cartridge casing ammunition must meet the reliability and performance standards of existing fielded ammunition and be interchangeable with brass cartridge casing ammunition in existing weaponry. Reliable cartridge casings manufacturing requires uniformity (e.g., bullet seating, bullet-to-casing fit, casing strength, etc.) from one cartridge to the next in order to obtain consistent pressures within the casing during firing prior to bullet and casing separation to create uniformed ballistic performance. Plastic cartridge casings have been known for many years but have failed to provide satisfactory ammunition that could be produced in commercial quantities with sufficient safety, ballistic, handling characteristics, and survive physical and natural conditions to which it will be exposed during the ammunition's intended life cycle; however, these characteristics have not been achieved.

For example, U.S. patent application Ser. No. 11/160,682 discloses a base for a cartridge casing body for an ammunition article, the base having an ignition device; an attachment device at one end thereof, the attachment device being adapted to the base to a cartridge casing body; wherein the base is made from plastic, ceramic, or a composite material.

U.S. Pat. No. 7,610,858 discloses an ammunition cartridge assembled from a substantially cylindrical polymeric cartridge casing body; and a cylindrical polymeric middle body component with opposing first and second ends, wherein the first end has a coupling element that is a mate for the projectile-end coupling element and joins the first end of the middle body component to the second end of the bullet-end component, and the second end is the end of the casing body opposite the projectile end and has a male or female coupling element; and a cylindrical cartridge casing head-end component with an essentially closed base end with a primer hole opposite an open end with a coupling element that is a mate for the coupling element on the second end of the middle body and joins the second end of the middle body component to the open end of the head-end component.

Shortcomings of the known methods of producing plastic or substantially plastic ammunition include the possibility of the projectile being pushed into the cartridge casing, the bullet pull being too light such that the bullet can fall out, the bullet pull being too insufficient to create sufficient chamber pressure, the bullet pull not being uniform from round to round, and portions of the cartridge casing breaking off upon firing causing the weapon to jam or damage or danger when subsequent rounds are fired or when the casing portions themselves become projectiles. To overcome the above shortcomings, improvements in cartridge case design and performance polymer materials are needed.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method of making a polymer ammunition cartridge having a metal injection molded primer insert comprising by the steps of: forming a substantially cylindrical metal primer insert by metal injection molding from a primer insert injection mold, wherein the substantially cylindrical metal primer insert comprises a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash aperture positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface; providing a first polymer composition for molding a polymer ammunition cartridge; molding from the first polymer composition a substantially cylindrical polymeric middle body having the substantially cylindrical metal primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the substantially cylindrical metal primer insert to the flange and extends over an interior surface of the substantially cylindrical coupling region to the primer flash hole aperture, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region to the primer flash hole aperture; forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region; and coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture.

Further comprising forming a primer flash aperture groove positioned in the primer recess around the primer flash aperture and the first polymer composition extends into the primer flash aperture to form a flash hole. The first polymer composition is the same as the second polymer composition. The first polymer composition is a ductile polymer. The first polymer composition, the second polymer composition or both comprise a nylon polymer. The first polymer composition, the second polymer composition or both comprise a fiber-reinforced polymeric composite. The first polymer composition, the second polymer composition or both comprise between about 10 and about 70 wt % glass fiber fillers, mineral fillers, or mixtures thereof. The bullet aperture comprises one or more cannelures formed on an inner circumferential surface of the bullet aperture. The substantially cylindrical coupling region and the polymeric bullet-end coupling are welded or bonded together. The first polymer composition, the second polymer composition or both comprise polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly(etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly(etherimide-siloxane) copolymers. A neck is positioned between the bullet aperture and the polymeric bullet-end coupling. Further including one or more internal structures in the neck to support a bullet. The bullet aperture comprises one, two, three, or more annular rings that mate with one, two, three, or more corresponding annular grooves positioned on the bullet.

The present invention provides a method of making a polymer ammunition cartridge having a metal injection molded primer insert comprising by the steps of: forming a substantially cylindrical metal primer insert by metal injection molding from a primer insert injection mold, wherein the substantially cylindrical metal primer insert comprises a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash aperture positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface; providing a first polymer composition for molding a polymer ammunition cartridge; molding from the first polymer composition a substantially cylindrical polymeric middle body having the substantially cylindrical metal primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the substantially cylindrical metal primer insert to the flange and extends over an interior surface of the substantially cylindrical coupling region to the primer flash hole aperture, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region to the primer flash hole aperture; forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region, a neck positioned between the bullet aperture and the polymeric bullet-end coupling and one or more cannelures formed on an inner circumferential surface of the bullet aperture; and coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures and in which:

FIG. 1 depicts a side, cross-sectional view of a polymeric cartridge case according to one embodiment of the present invention;

FIG. 2 depicts a side, cross-sectional view of a portion of the polymeric cartridge case according to one embodiment of the present invention;

FIG. 3 depicts a side, cross-sectional view of a portion of the polymeric cartridge case lacking the polymer coating over the flash hole aperture;

FIGS. 4a and 4b depict images of a catastrophic failure of the polymeric cartridge case of FIG. 3;

FIG. 5 depicts a side, cross-sectional view of a portion of the polymeric cartridge case displaying ribs according to one embodiment of the present invention;

FIG. 6 depicts a side, cross-sectional view of a portion of the polymeric cartridge case displaying ribs according to one embodiment of the present invention;

FIG. 7 depicts a side, cross-sectional view of a polymeric cartridge case having a diffuser according to one embodiment of the present invention;

FIG. 8 depicts a side, cross-sectional view of a portion of the polymeric cartridge case having a diffuser according to one embodiment of the present invention;

FIGS. 9a-9h depict the diffuser according to a different embodiment of the present invention;

FIG. 10 depicts a perspective view of one embodiment of a substantially cylindrical primer insert;

FIG. 11 depicts a cross-sectional view of a substantially cylindrical primer insert according to one embodiment of the present invention;

FIG. 12 depicts a cross-sectional view of the substantially cylindrical primer insert according to FIG. 11 rotated 90 degrees relative to FIG. 5; and

FIGS. 13A-13O depict a perspective view of various different embodiments of the substantially cylindrical primer insert of the present invention.

FIG. 14 depicts an exploded view of the polymeric cartridge casing;

FIGS. 15A and 15B depict a view of the substantially cylindrical open-ended polymeric bullet-end having a shoulder forming chamber neck and a bullet; and

FIG. 16 depicts an elevation view of a bullet-end component of the polymeric cartridge casing; and

FIG. 17 depicts a side, cross-sectional view of a bullet-end component of the polymeric cartridge casing.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.

Reliable cartridge manufacture requires uniformity from one cartridge to the next in order to obtain consistent ballistic performance. Among other considerations, proper bullet seating and bullet-to-casing fit is required. In this manner, a desired pressure develops within the casing during firing prior to bullet and casing separation. Historically, bullets employ a cannelure, which is a slight annular depression formed in a surface of the bullet at a location determined to be the optimal seating depth for the bullet. In this manner, a visual inspection of a cartridge could determine whether or not the bullet is seated at the proper depth. Once the bullet is inserted into the casing to the proper depth, one of two standard procedures is incorporated to lock the bullet in its proper location. One method is the crimping of the entire end of the casing into the cannelure. A second method does not crimp the casing end; rather the bullet is pressure fitted into the casing.

The polymeric ammunition cartridges of the present invention are of a caliber typically carried by soldiers in combat for use in their combat weapons. The present invention is not limited to the described caliber and is believed to be applicable to other calibers as well. This includes various small and medium caliber munitions, including 5.56 mm, 7.62 mm, 308, 338, 3030, 3006, and 0.50 caliber ammunition cartridges, as well as medium/small caliber ammunition such as 380 caliber, 38 caliber, 9 mm, 10 mm, 20 mm, 25 mm, 30 mm, 40 mm, 45 caliber and the like. The cartridges, therefore, are of a caliber between about 0.05 and about 5 inches. Thus, the present invention is also applicable to the sporting goods industry for use by hunters and target shooters.

One embodiment of the present invention includes a substantially cylindrical insert mold for making a substantially cylindrical insert by metal injection molding comprising: a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface; a primer recess in the top surface that extends toward the bottom surface; a primer flash hole positioned in the primer recess to extend through the bottom surface; and a flange that extends circumferentially about an outer edge of the top surface.

Still another embodiment includes a method of forming a polymeric ammunition cartridge by providing a substantially cylindrical insert having a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash hole positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface, forming a substantially cylindrical polymeric middle body comprising a substantially cylindrical polymeric bullet-end and a substantially cylindrical polymeric coupling end connected by a powder chamber, connecting the substantially cylindrical polymeric coupling end to the substantially cylindrical coupling element; and covering circumferentially an interior surface of the primer flash hole. The method further includes the step of positioning a diffuser comprising a diffuser flash hole in the primer recess and aligning the diffuser flash hole with the primer flash hole.

FIG. 1 depicts a side, cross-sectional view of a polymeric cartridge case according to one embodiment of the present invention. A cartridge 10 suitable for use with high velocity rifles is shown manufactured with a polymer casing 12 showing a propellant chamber 14 with projectile (not shown) inserted into the forward end opening 16. The polymer casing 12 has a substantially cylindrical open-ended polymeric bullet-end 18 extending from forward end opening 16 rearward to opposite end 20. The bullet-end component 18 may be formed with the coupling end 22 formed on the end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The forward end of bullet-end component 18 has a shoulder 24 forming chamber neck 26. The bullet-end component typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches.

The middle body component 28 is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations is acceptable for the coupling elements 30 and the coupling end 22 in alternate embodiments of the invention. The coupling end 22 of bullet-end component 18 fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole 40 is located in the primer flash hole 40 and extends through the bottom surface 34 into the propellant chamber 14. The coupling end 22 extends the polymer through the primer flash hole 40 to form an aperture coating 42 while retaining a passage from the top surface 36 through the bottom surface 34 and into the propellant chamber 14 to provide support and protection about the primer flash hole 40. When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 and middle body component 28. The polymer casing 12 also has a substantially cylindrical open-ended middle body component 28. The middle body component extends from a forward end opening 16 to the coupling element 22. The middle body component typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. The bullet-end 16, middle body 18 and bottom surface 34 define the interior of propellant chamber 14 in which the powder charge (not shown) is contained. The interior volume of propellant chamber 14 may be varied to provide the volume necessary for complete filling of the chamber 14 by the propellant chosen so that a simplified volumetric measure of propellant can be utilized when loading the cartridge. Either a particulate or consolidated propellant can be used.

The substantially cylindrical insert 32 also has a flange 46 cut therein and a primer recess 38 formed therein for ease of insertion of the primer (not shown). The primer recess 38 is sized so as to receive the primer (not shown) in an interference fit during assembly. A primer flash hole 40 communicates through the bottom surface 34 of substantially cylindrical insert 32 into the propellant chamber 14 so that upon detonation of primer (not shown) the powder in propellant chamber 14 will be ignited.

The projectile (not shown) is held in place within chamber case neck 26 at forward opening 16 by an interference fit. Mechanical crimping of the forward opening 16 can also be applied to increase the bullet pull force. The bullet (not shown) may be inserted into place following the completion of the filling of propellant chamber 14. The projectile (not shown) can also be injection molded directly onto the forward opening 16 prior to welding or bonding together using solvent, adhesive, spin-welding, vibration-welding, ultrasonic-welding or laser-welding techniques. The welding or bonding increases the joint strength so the casing can be extracted from the hot gun casing after firing at the cook-off temperature.

The bullet-end and bullet components can then be welded or bonded together using solvent, adhesive, spin-welding, vibration-welding, ultrasonic-welding or laser-welding techniques. The welding or bonding increases the joint strength so the casing can be extracted from the hot gun casing after firing at the cook-off temperature. An optional first and second annular grooves (cannelures) may be provided in the bullet-end in the interlock surface of the male coupling element to provide a snap-fit between the two components. The cannelures formed in a surface of the bullet at a location determined to be the optimal seating depth for the bullet. Once the bullet is inserted into the casing to the proper depth to lock the bullet in its proper location. One method is the crimping of the entire end of the casing into the cannelures.

The bullet-end and middle body components can then be welded or bonded together using solvent, adhesive, spin-welding, vibration-welding, ultrasonic-welding or laser-welding techniques. The welding or bonding increases the joint strength so the casing can be extracted from the hot gun casing after firing at the cook-off temperature.

FIG. 2 depicts a side, cross-sectional view of a portion of the polymeric cartridge case according to one embodiment of the present invention. A portion of a cartridge suitable for use with high velocity rifles is shown manufactured with a polymer casing 12 showing a propellant chamber 14. The polymer casing 12 has a substantially cylindrical opposite end 20. The bullet-end component 18 may be formed with the coupling end 22 formed on end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The middle body component (not shown) is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations is acceptable for the coupling elements 30 and the coupling end 22 in alternate embodiments of the invention. The coupling end 22 fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole 40 is located in the primer recess 28 and extends through the bottom surface 34 into the propellant chamber 14. The coupling end 22 extends the polymer through the primer flash hole 40 to form an aperture coating 42 while retaining a passage from the top surface 36 through the bottom surface 34 and into the propellant chamber 14 to provide support and protection about the primer flash hole 40. When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 and middle body component 28. The polymer casing 12 also has a substantially cylindrical open-ended middle body component 28.

FIG. 3 depicts a side, cross-sectional view of a portion of the polymeric cartridge case lacking the aperture coating (not shown). A portion of a cartridge suitable for use with high velocity rifles is shown manufactured with a polymer casing (not shown) showing a powder chamber 14. The polymer casing (not shown) has a substantially cylindrical opposite end 20. The bullet-end component (not shown) may be formed with the coupling end 22 formed on end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The middle body component (not shown) is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations are acceptable for the coupling elements 30 and coupling end 22 in alternate embodiments of the invention. The coupling end 22 fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole (not shown) is located in the primer recess 28 and extends through the bottom surface 34 into the powder chamber 14. When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip (not shown) to form a physical interlock between substantially cylindrical insert 32 also has a flange 46 cut therein and middle body component (not shown).

FIGS. 4a and 4b depict images of a catastrophic failure of the polymeric cartridge case of FIG. 3. Other polymeric cartridge case was tested and resulted in catastrophic failure with the rounds blowing the magazine out of the weapon and fragmenting the metal insert and lodging the polymer case in the chamber. The examination of the catastrophic failure revealed the tearing of the polymer at the top of the insert. As a result, in some embodiments the height of the insert was reduced by 0.020″ to reduce the tearing and frequency of catastrophic failures. Further examination, revealed that the polymer at the flash hole of the base was separating from the insert. One embodiment locks the polymer into the flash hole by extending the polymer into the flash hole. In addition, the raised area was removed, the diameter of the flash hole was opened, and the primer side was counter bored. Other embodiments may incorporate all, one, or a combination of 2 or more of these elements to stop the gas from separating the polymer from the insert that was creating combustion between the insert and the polymer.

FIG. 5 depicts a side, cross-sectional view of a portion of the polymeric cartridge case displaying ribs according to one embodiment of the present invention. A portion of a cartridge suitable for use with high velocity rifles is shown manufactured with a polymer casing (not shown) showing a powder chamber 14. The polymer casing (not shown) has a substantially cylindrical opposite end 20. The bullet-end component 18 may be formed with the coupling end 22 formed on end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The middle body component (not shown) is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations is acceptable for coupling elements 30 and coupling end 22 in alternate embodiments of the invention. The coupling end 22 fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30, extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole 40 is located in the primer recess 28 and extends through the bottom surface 34 into the powder chamber 14. The coupling end 22 extends the polymer through the primer flash hole 40 to form an aperture coating 42 while retaining a passage from the top surface 36 through the bottom surface 34 and into the powder chamber 14 to provide support and protection about the primer flash hole 40. When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 also has a flange 46 cut therein and middle body component 28. The polymer casing (not shown) also has a substantially cylindrical open-ended middle body component 28. The substantially cylindrical opposite end 20 or anywhere within the powder chamber 14 may include one or more ribs 48 on the surface. The number of ribs 48 will depend on the specific application and desire of the manufacture but may include 1, 2, 3, 4, 5 6, 7, 8, 9, 10, or more ribs. In the counter bore, the polymer was having difficulty filling this area due to the fact that the polymer used has fillers in it, and needed to be reblended during molding. One embodiment includes six ribs 48 to create turbulence in the flow of the polymer, thus allowing the material to fill the counter bore.

FIG. 6 depicts a side, cross-sectional view of a portion of the polymeric cartridge case displaying ribs according to one embodiment of the present invention. One embodiment that reduces bellowing of the insert includes a shortened insert and angled the coupling element 30 inside of the insert. In addition, the raised portion of the polymer at the flash hole was removed, the internal polymer wall was lowered and angled to match the insert and the internal ribs were lengthened.

A portion of a cartridge suitable for use with high velocity rifles is shown manufactured with a polymer casing (not shown) showing a powder chamber 14. The polymer casing (not shown) has a substantially cylindrical opposite end 20. The bullet-end component (not shown) may be formed with coupling end 22 formed on end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The middle body component (not shown) is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations are acceptable for the coupling elements 30 and the coupling end 22 in alternate embodiments of the invention. The coupling end 22 fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole 40 is located in the primer recess 28 and extends through the bottom surface 34 into the powder chamber 14. The coupling end 22 extends the polymer through the primer flash hole 40 to form an aperture coating 42 while retaining a passage from the top surface 36 through the bottom surface 34 and into the powder chamber 14 to provide support and protection about the primer flash hole 40. When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 and middle body component 28. The polymer casing (not shown) also has a substantially cylindrical open-ended middle body component 28. The substantially cylindrical opposite end 20 or anywhere within the powder chamber 14 may include one or more ribs 48 on the surface. The number of ribs 48 will depend on the specific application and desire of the manufacture but may include 1, 2, 3, 4, 5 6, 7, 8, 9, 10, or more ribs. In the counter bore, the polymer was having difficulty filling this area due to the fact that the polymer used has fillers in it, and needed to be reblended during molding. One embodiment includes six ribs 48 to create turbulence in the flow of the polymer, thus allowing the material to fill the counter bore. Another embodiment of the present invention is a shortened insert and angled coupling element 30 inside of the insert. In addition, raised portions of the polymer at the flash hole, lowered and angled the internal polymer wall to match the insert and lengthened the internal ribs.

FIG. 7 depicts a side, cross-sectional view of a polymeric cartridge case having a diffuser according to one embodiment of the present invention. The diffuser (not shown) is a device that is used to divert the affects of the primer off of the polymer and directing it to the flash hole. The affects being the impact from igniting the primer as far as pressure and heat. A cartridge 10 suitable for use with high velocity rifles is shown manufactured with a polymer casing (not shown) showing a powder chamber 14 with projectile (not shown) inserted into the forward end opening 16. The polymer casing (not shown) has a substantially cylindrical open-ended polymeric bullet-end 18 extending from forward end opening 16 rearward to the opposite end 20. The bullet-end component (not shown) may be formed with the coupling end 22 formed on the end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The forward end of bullet-end component 18 has a shoulder 24 forming chamber neck 26.

The middle body component 28 is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations is acceptable for the coupling elements 30 and the coupling end 22 in alternate embodiments of the invention. The coupling end 22 of bullet-end component 18 fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole 40 is located in the primer recess 28 and extends through the bottom surface 34 into the powder chamber 14. The coupling end 22 extends the polymer through the primer flash hole 40 to form an aperture coating 42 while retaining a passage from the top surface 36 through the bottom surface 34 and into the powder chamber 14 to provides support and protection about the primer flash hole 40. When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 also has a flange 46 cut therein and middle body component 28. The polymer casing 12 also has a substantially cylindrical open-ended middle body component 28. The middle body component extends from a forward end opening 16 to the coupling element 22. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34 with a diffuser (not shown) positioned in the primer recess 38. The diffuser (not shown) includes a diffuser aperture (not shown) that aligns with the primer flash hole 40. The diffuser (not shown) is a device that is used to divert the affects of the primer (not shown) off of the polymer. The affects being the impact from igniting the primer as far as pressure and heat to divert the energy of the primer off of the polymer and directing it to the flash hole.

FIG. 8 depicts a side, cross-sectional view of a portion of the polymeric cartridge case having a diffuser according to one embodiment of the present invention. A portion of a cartridge suitable for use with high velocity rifles is shown manufactured with a polymer casing (not shown) showing a powder chamber 14. The polymer casing (not shown) has a substantially cylindrical opposite end 20. The bullet-end component (not shown) may be formed with the coupling end 22 formed on the end 20. The coupling end (not shown) is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The middle body component (not shown) is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The coupling element 30, as shown may be configured as a male element, however, all combinations of male and female configurations are acceptable for the coupling elements 30 and the coupling end (not shown) in alternate embodiments of the invention. The coupling end (not shown) fits about and engages the coupling element 30 of a substantially cylindrical insert 32. The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface (not shown) that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface (not shown). A primer flash hole 40 extends through the bottom surface (not shown) into the powder chamber 14. The coupling end (not shown) extends the polymer through the primer flash hole 40 to form an aperture coating 42 while retaining a passage from the top surface 36 through the bottom surface (not shown) and into the powder chamber 14 to provides support and protection about the primer flash hole 40. When contacted the coupling end (not shown) interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 also has a flange 46 cut therein and middle body component 28. The polymer casing (not shown) also has a substantially cylindrical open-ended middle body component 28. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface (not shown) with a diffuser 50 positioned in the primer recess 38. The diffuser (not shown) includes a diffuser aperture 52 and a diffuser aperture extension 54 that aligns with the primer flash hole 40. The diffuser 50 is a device that is used to divert the affects of the primer (not shown) off of the polymer. The affects being the impact from igniting the primer as far as pressure and heat to divert the energy of the primer off of the polymer and directing it to the flash hole. The diffuser 50 can be between 0.004 to 0.010 inches in thickness and made from half hard brass. For example, the diffuser 50 can be between 0.005 inches thick for a 5.56 diffuser 50. The outer diameter of the diffuser for a 5.56 or 223 case is 0.173 and the inner diameter is 0.080. The Diffuser could be made of any material that can withstand the energy from the ignition of the primer. This would include steel, stainless, cooper, aluminum or even an engineered resin that was injection molded or stamped. The Diffuser can be produce in T shape by drawing the material with a stamping and draw die. In the T Diffuser the center ring can be 0.005 to 0.010 tall and the outer diameter is 0.090 and the inner diameter 0.080.

FIGS. 9a-9h depict different embodiment of the diffuser of the present invention.

FIG. 10 depicts a perspective view of a substantially cylindrical primer insert according to one embodiment of the present invention. The substantially cylindrical primer insert 32 has an optional flange 46 cut therein and a primer recess (not shown) formed therein for ease of insertion of the primer recess (not shown). The flange 46 extends circumferentially about the outer edge of the substantially cylindrical primer insert 32. The primer recess (not shown) is sized so as to receive the primer in an interference fit during assembly. A series of notches 42 are placed along the exterior circumference of substantially cylindrical primer insert 32 circling the primer recess (not shown) between flange 46 and coupling element 30. The coupling element 30 extends from a bottom surface (not shown) to a coupling tip 44. The design, shape and number of notches 42 will depend on the specific application and desire of the manufacture but may include 1, 2, 3, 4, 5 6, 7, 8, 9, 10, or more notches.

FIG. 11 depicts a cross-sectional view of a substantially cylindrical primer insert 32 according to one embodiment of the present invention. The substantially cylindrical primer insert 32 has a flange 46 cut that extends circumferentially about an outer edge of the top surface 36. A primer recess 38 in the top surface 36 extends from top surface 36 towards a bottom surface 34. The substantially cylindrical primer insert 32 also includes a coupling element 30 that extends from the bottom surface 34 to a coupling tip 44. A primer flash hole 40 is positioned in the primer recess 38 and extends through the bottom surface 34 into an insert opening 48 in the coupling element 30. When contacted with the rest of the cartridge (not shown), the cartridge interlocks with the coupling element 30.

The metal injection molding process of making the substantially cylindrical primer insert 32 mold shown is made in the shape of the substantially cylindrical primer insert 32 includes the desired profile of the primer recess 38. The substantially cylindrical primer insert 32 includes a coupling element 30 extending from a bottom surface 34 that is opposite a top surface 36. Located in the top surface 36 is a primer recess 38 that extends toward the bottom surface 34. A primer flash hole 38 is located in the substantially cylindrical primer insert 32 and extends through the bottom surface 34 into the insert opening 48.

FIG. 12 depicts a rotated, cross-sectional view of a portion of the substantially cylindrical primer insert 32 according to one embodiment of the present invention. The substantially cylindrical primer insert 32 has a flange 46 cut that extends circumferentially about an outer edge of the top surface 36. A primer recess 38 in the top surface 36 extends from top surface 36 towards a bottom surface 34. A notch 42 adjacent to the primer recess 38 extends from flange 46 towards bottom surface 34. The gas generator insert 32 also includes a coupling element 30 that extends from the bottom surface 34 to a coupling tip 44. A primer flash hole 40 is positioned in the primer recess 38 and extends through the bottom surface 34 into an insert opening 48.

FIGS. 13A-13O depict perspective views of a substantially cylindrical primer inserts according to various embodiments of the present invention. FIGS. 13A-13O illustrate the shape of the substantially cylindrical primer insert; however other shapes and variations are contemplated. The flange on the substantially cylindrical primer insert is optional and the notches can be of any number, shape, or design including scallop shaped, wing shaped, prism shaped, rectangular shaped and the like.

FIG. 13A shows a perspective view of an embodiment of the substantially cylindrical primer insert 32 wherein the notches 42 is a triangular prism extending from flange 46 towards bottom surface 34 (not shown). FIG. 13B shows another embodiment of substantially cylindrical primer insert 32 with an increased number of notches 42 as triangular prisms positioned on flange 46. The number of notches 42 can be tailored to the specific application and need of the manufacturer.

FIG. 13C shows a perspective view of an embodiment of the substantially cylindrical primer insert 32 wherein the notches 42 are redesigned as a band 50. Band 50 provides the same lateral support as notches 42 around the primer recess 38 (not shown) and is also positioned on flange 46.

FIG. 13D shows a perspective view of an embodiment of the substantially cylindrical primer insert 32 wherein the notches 42 are redesigned into the shape of a laterally extruded half cylinder. The notches 42 are positioned on flange 46 and extend toward bottom surface 34 (not shown). FIGS. 13E and 13F show additional variations embodiment of the substantially cylindrical primer insert 32 with different numbers of notches 42 positioned on flange 46. The different embodiments show different spacing between each of the notches 42. The number of notches 42 and the spacing between each of them can be tailored to the specific application.

FIG. 13G shows a perspective view of another embodiment of the substantially cylindrical primer insert 32 with wider laterally extruded half cylinder notches 42 positioned on flange 46. The size and design of the notches 42 as well as its placement and the spacing between them can be tailored to the specific application.

FIG. 13H shows a perspective view of another embodiment of a substantially cylindrical primer insert 32 where the notches 42 are scallop shaped and continuous. There is no spacing between the series of connected notches 42 positioned on top of flange 46. The connected scallop shaped notches 42 surround the outer casing of the primer recess 38 (not shown). FIG. 13I shows another embodiment of the substantially cylindrical primer insert 32 with continuous scallop notches 42 with a different number of scallop notches 42 positioned on flange 46. The number and width of notches 42 can be tailored to the specific application.

FIGS. 13J and 13K show a perspective view of different embodiment of the substantially cylindrical primer insert 32 wherein the notches 42 are scallop shaped and continuous, but the coupling element 30 are of varying lengths or height. FIG. 13J shows an embodiment with a shorter coupling element 30. FIG. 13K shows an embodiment with a taller coupling element 30 of the substantially cylindrical primer insert. The height or length of coupling element 30 can be tailored to the specific application and need.

FIG. 13L shows another embodiment of the substantially cylindrical primer insert 32 wherein the notches 42 is scallop shaped and continuous, but has a smaller curvature profile. The size, length, numbering, and curvature of the notches 42 can be tailored to the specific application and need.

FIG. 13M shows another embodiment of the substantially cylindrical primer insert 32 wherein there are no notches 42 positioned on flange 46.

FIG. 13N shows another embodiment of the substantially cylindrical primer insert 32 wherein notches 42 are replaced by band 50, but band 50 includes a series of bands with different profiles and heights. The thickness, number, height, and profile of band 50 positioned on flange 46 and wrapping around primer recess 38 (not shown) can be tailored to the specific application and need of the manufacturer.

FIG. 13O shows another embodiment of the substantially cylindrical primer insert 32 wherein notches 42 are a series of different shapes with different thicknesses and designs, as well as different spacing in between each and no set number when positioned on flange 46. The number, shape, design, and spacing of notches 42 can be tailored to the specific application and is not limited to recurring similar shapes or designs.

Another embodiment of the present invention having a top surface opposite a bottom surface and a coupling element that extends from the bottom surface away from the top surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash hole positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface.

For example, the metal injection molding process, which generally involves mixing fine metal powders with binders to form a feedstock that is injection molded into a closed mold, may be used to form a substantially cylindrical insert. After ejection from the mold, the binders are chemically or thermally removed from the substantially cylindrical insert so that the part can be sintered to high density. During the sintering process, the individual metal particles metallurgically bond together as material diffusion occurs to remove most of the porosity left by the removal of the binder.

The raw materials for metal injection molding are metal powders and a thermoplastic binder. There are at least two Binders included in the blend, a primary binder and a secondary binder. This blended powder mix is worked into the plasticized binder at elevated temperature in a kneader or shear roll extruder. The intermediate product is the so-called feedstock. It is usually granulated with granule sizes of several millimeters. In metal injection molding, only the binders are heated up, and that is how the metal is carried into the mold cavity.

In preparing a feedstock, it is important first to measure the actual density of each lot of both the metal powders and binders. This is extremely important especially for the metal powders in that each lot will be different based on the actual chemistry of that grade of powder. For example, 316L is comprised of several elements, such as Fe, Cr, Ni, Cu, Mo, P, Si, S and C. In order to be rightfully called a 316L, each of these elements must meet a minimum and maximum percentage weight requirement as called out in the relevant specification. Tables I-IV below provide other examples of the elemental compositions of some of the metal powders, feed stocks, metals, alloys and compositions of the present invention. Hence the variation in the chemistry within the specification results in a significant density variation within the acceptable composition range. Depending on the lot received from the powder producer, the density will vary depending on the actual chemistry received.

TABLE I Material Designation Chemical Composition, % − Low-Alloy Steels Code Fe Ni Mo C Si (max) MIM-2200⁽¹⁾ Bal. 1.5 − 2.5 0.5 max 0.1 max 1.0 MIM-2700 Bal. 6.5 − 8.5 0.5 max 0.1 max 1.0 MIM-4605⁽²⁾ Bal. 1.5 − 2.5 0.2 − 0.5 0.4 − 0.6 1.0

TABLE II Material Designation Chemical Composition, % - Stainless Steels Code Fe Ni Cr Mo C Cu Nb + Ta Mn (max) Si (max) MIM-316L Bal. 10-14 16-18 2-3 0.03 max — — 2.0 1.0 MIM-420 Bal. — 12-14 — 0.15-0.4 — — 1.0 1.0 MIM-430L Bal. — 16-18 — 0.05 max — — 1.0 1.0 MIM-17-4 PH Bal. 3-5 15.5-17.5 — 0.07 max 3-5 0.15-0.45 1.0 1.0

TABLE III Material Designation Chemical Composition, % - Soft-Magnetic Alloys Code Fe Ni Cr Co Si C (max) Mn V MIM-2200 Bal. 1.5-2.5 — — 1.0 max 0.1 — — MIM-Fe—3% Si Bal. — — — 2.5-3.5 0.05 — — MIM-Fe50% Ni Bal. 49-51 — — 1.0 max 0.05 — — MIM-Fe50% Co Bal. — — 48-50 1.0 max 0.05 — 2.5 max MIM-430L Bal. — 16-18 — 1.0 max 0.05 1.0 max —

TABLE IV Nominal Chemical Composition, % - Controlled-Expansion Alloys Material Mn Si C Al Mg Zr Ti Cu Cr Mo Designation Fe Ni Co max max max max max max max max max max MIM-F15 Bal. 29 17 0.50 0.20 0.04 0.10 0.10 0.10 0.10 0.20 0.20 0.20

In addition to the specific compositions listed herein, the skill artisan recognizes the elemental composition of common commercial designations used by feedstock manufacturers and processors, e.g., C-0000 Copper and Copper Alloys; CFTG-3806-K Diluted Bronze Bearings; CNZ-1818 Copper and Copper Alloys; CNZP-1816 Copper and Copper Alloys; CT-1000 Copper and Copper Alloys; CT-1000-K Bronze Bearings; CTG-1001-K Bronze Bearings; CTG-1004-K Bronze Bearings; CZ-1000 Copper and Copper Alloys; CZ-2000 Copper and Copper Alloys; CZ-3000 Copper and Copper Alloys; CZP-1002 Copper and Copper Alloys; CZP-2002 Copper and Copper Alloys; CZP-3002 Copper and Copper Alloys; F-0000 Iron and Carbon Steel; F-0000-K Iron and Iron-Carbon Bearings; F-0005 Iron and Carbon Steel; F-0005-K Iron and Iron-Carbon Bearings; F-0008 Iron and Carbon Steel; F-0008-K Iron and Iron-Carbon Bearings; FC-0200 Iron-Copper and Copper Steel; FC-0200-K Iron-Copper Bearings; FC-0205 Iron-Copper and Copper Steel; FC-0205-K Iron-Copper-Carbon Bearings; FC-0208 Iron-Copper and Copper Steel; FC-0208-K Iron-Copper-Carbon Bearings; FC-0505 Iron-Copper and Copper Steel; FC-0508 Iron-Copper and Copper Steel; FC-0508-K Iron-Copper-Carbon Bearings; FC-0808 Iron-Copper and Copper Steel; FC-1000 Iron-Copper and Copper Steel; FC-1000-K Iron-Copper Bearings; FC-2000-K Iron-Copper Bearings; FC-2008-K Iron-Copper-Carbon Bearings; FCTG-3604-K Diluted Bronze Bearings; FD-0200 Diffusion-Alloyed Steel; FD-0205 Diffusion-Alloyed Steel; FD-0208 Diffusion-Alloyed Steel; FD-0400 Diffusion-Alloyed Steel; FD-0405 Diffusion-Alloyed Steel; FD-0408 Diffusion-Alloyed Steel; FF-0000 Soft-Magnetic Alloys; FG-0303-K Iron-Graphite Bearings; FG-0308-K Iron-Graphite Bearings; FL-4005 Prealloyed Steel; FL-4205 Prealloyed Steel; FL-4400 Prealloyed Steel; FL-4405 Prealloyed Steel; FL-4605 Prealloyed Steel; FL-4805 Prealloyed Steel; FL-48105 Prealloyed Steel; FL-4905 Prealloyed Steel; FL-5208 Prealloyed Steel; FL-5305 Prealloyed Steel; FLC-4608 Sinter-Hardened Steel; FLC-4805 Sinter-Hardened Steel; FLC-48108 Sinter-Hardened Steel; FLC-4908 Sinter-Hardened Steel; FLC2-4808 Sinter-Hardened Steel; FLDN2-4908 Diffusion-Alloyed Steel; FLDN4C2-4905 Diffusion-Alloyed Steel; FLN-4205 Hybrid Low-Alloy Steel; FLN-48108 Sinter-Hardened Steel; FLN2-4400 Hybrid Low-Alloy Steel; FLN2-4405 Hybrid Low-Alloy Steel; FLN2-4408 Sinter-Hardened Steel; FLN2C-4005 Hybrid Low-Alloy Steel; FLN4-4400 Hybrid Low-Alloy Steel; FLN4-4405 Hybrid Low-Alloy Steel; FLN4-4408 Sinter Hardened Steel; FLN4C-4005 Hybrid Low-Alloy Steel; FLN6-4405 Hybrid Low-Alloy Steel; FLN6-4408 Sinter-Hardened Steel; FLNC-4405 Hybrid Low-Alloy Steel; FLNC-4408 Sinter-Hardened Steel; FN-0200 Iron-Nickel and Nickel Steel; FN-0205 Iron-Nickel and Nickel Steel; FN-0208 Iron-Nickel and Nickel Steel; FN-0405 Iron-Nickel and Nickel Steel; FN-0408 Iron-Nickel and Nickel Steel; FN-5000 Soft-Magnetic Alloys; FS-0300 Soft-Magnetic Alloys; FX-1000 Copper-Infiltrated Iron and Steel; FX-1005 Copper-Infiltrated Iron and Steel; FX-1008 Copper-Infiltrated Iron and Steel; FX-2000 Copper-Infiltrated Iron and Steel; FX-2005 Copper-Infiltrated Iron and Steel; FX-2008 Copper-Infiltrated Iron and Steel; FY-4500 Soft-Magnetic Alloys; FY-8000 Soft-Magnetic Alloys; P/F-1020 Carbon Steel PF; P/F-1040 Carbon Steel PF; P/F-1060 Carbon Steel PF; P/F-10C40 Copper Steel PF; P/F-10C50 Copper Steel PF; P/F-10C60 Copper Steel PF; P/F-1140 Carbon Steel PF; P/F-1160 Carbon Steel PF; P/F-11C40 Copper Steel PF; P/F-11050 Copper Steel PF; P/F-11C60 Copper Steel PF; P/F-4220 Low-Alloy P/F-42XX Steel PF; P/F-4240 Low-Alloy P/F-42XX Steel PF; P/F-4260 Low-Alloy P/F-42XX Steel PF; P/F-4620 Low-Alloy P/F-46XX Steel PF; P/F-4640 Low-Alloy P/F-46XX Steel PF; P/F-4660 Low-Alloy P/F-46XX Steel PF; P/F-4680 Low-Alloy P/F-46XX Steel PF; SS-303L Stainless Steel—300 Series Alloy; SS-303N1 Stainless Steel—300 Series Alloy; SS-303N2 Stainless Steel—300 Series Alloy; SS-304H Stainless Steel—300 Series Alloy; SS-304L Stainless Steel—300 Series Alloy; SS-304N1 Stainless Steel—300 Series Alloy; SS-304N2 Stainless Steel—300 Series Alloy; SS-316H Stainless Steel—300 Series Alloy; SS-316L Stainless Steel—300 Series Alloy; SS-316N1 Stainless Steel—300 Series Alloy; SS-316N2 Stainless Steel—300 Series Alloy; SS-409L Stainless Steel—400 Series Alloy; SS-409LE Stainless Steel—400 Series Alloy; SS-410 Stainless Steel—400 Series Alloy; SS-410L Stainless Steel—400 Series Alloy; SS-430L Stainless Steel—400 Series Alloy; SS-430N2 Stainless Steel—400 Series Alloy; SS-434L Stainless Steel—400 Series Alloy; SS-434LCb Stainless Steel—400 Series Alloy; and SS-434N2 Stainless Steel—400 Series Alloy.

One embodiment of the substantially cylindrical metal primer insert may include a composition where Ni may be 2.0, 2.25, 2.50, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.50, 4.75, 5.0, 5.25, 5.5, 5.75, 6.0, 6.25, 6.50, 6.75, 7.0, 7.25, 7.5, 7.75, 8.0, 8.25, 8.50, 8.75, 9.0, 9.25, 9.5, 9.75, 10.0, 10.25, 10.50, 10.75, 11.0, 11.25, 11.5, 11.75, 12.0, 12.25, 12.50, 12.75, 13.0, 13.25, 13.5, 13.75, 14.0, 14.25, 14.50, 14.75, 15.0, 15.25, 15.5, 15.75, 16.0, 16.25, 16.50, 16.75, or 17.0%; Cr may be 9.0, 9.25, 9.5, 9.75, 10.0, 10.25, 10.50, 10.75, 11.0, 11.25, 11.5, 11.75, 12.0, 12.25, 12.50, 12.75, 13.0, 13.25, 13.5, 13.75, 14.0, 14.25, 14.50, 14.75, 15.0, 15.25, 15.5, 15.75, 16.0, 16.25, 16.50, 16.75, 17.0, 17.25, 17.5, 17.75, 18.0, 18.25, 18.50, 18.75, 19.0, 19.25, 19.5, 19.75, or 20.0%; Mo may be 0.00, 0.025, 0.050, 0.075, 0.10, 0.125, 0.150, 0.175, 0.20, 0.225, 0.250, 0.275, 0.30, 0.325, 0.350, 0.375, 0.40, 0.425, 0.450, 0.475, 0.50, 0.525, 0.550, 0.575, 0.60, 0.625, 0.650, 0.675, 0.70, 0.725, 0.750, 0.775, 0.80, 0.825, 0.850, 0.875, 0.90, 0.925, 0.950, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.50, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.50, 4.75, 5.0, 5.25, 5.5, 5.75, 6.0, 6.25, 6.50, 6.75, or 7.0%; C may be 0.00, 0.025, 0.050, 0.075, 0.10, 0.125, 0.150, 0.175, 0.20, 0.225, 0.250, 0.275, 0.30, 0.325, 0.350, 0.375, 0.40, 0.425, 0.450, 0.475, 0.50, 0.525, 0.550, 0.575, 0.60, 0.625, 0.650, 0.675, 0.70, 0.725, 0.750, 0.775, 0.80, 0.825, 0.850, 0.875, 0.90, 0.925, 0.950, or 1.00%; Cu may be 0.00, 0.025, 0.050, 0.075, 0.10, 0.125, 0.150, 0.175, 0.20, 0.225, 0.250, 0.275, 0.30, 0.325, 0.350, 0.375, 0.40, 0.425, 0.450, 0.475, 0.50, 0.525, 0.550, 0.575, 0.60, 0.625, 0.650, 0.675, 0.70, 0.725, 0.750, 0.775, 0.80, 0.825, 0.850, 0.875, 0.90, 0.925, 0.950, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.50, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.50, 4.75, 5.0, 5.25, 5.5, 5.75, 6.0, 6.25, 6.50, 6.75, 7.0, 7.25, 7.5, 7.75, or 8.0%; Nb+Ta may be 0.00, 0.025, 0.050, 0.075, 0.10, 0.125, 0.150, 0.175, 0.20, 0.225, 0.250, 0.275, 0.30, 0.325, 0.350, 0.375, 0.40, 0.425, 0.450, 0.475, 0.50, 0.525, 0.550, 0.575, 0.60, 0.625, 0.650, 0.675, 0.70, 0.725, 0.750, 0.775, or 0.80%; Mn may be 0.00, 0.025, 0.050, 0.075, 0.10, 0.125, 0.150, 0.175, 0.20, 0.225, 0.250, 0.275, 0.30, 0.325, 0.350, 0.375, 0.40, 0.425, 0.450, 0.475, 0.50, 0.525, 0.550, 0.575, 0.60, 0.625, 0.650, 0.675, 0.70, 0.725, 0.750, 0.775, 0.80, 0.825, 0.850, 0.875, 0.90, 0.925, 0.950, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.50, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.50, 4.75, 5.0, 5.25, 5.5, 5.75, or 6.0%; Si may be 0.00, 0.025, 0.050, 0.075, 0.10, 0.125, 0.150, 0.175, 0.20, 0.225, 0.250, 0.275, 0.30, 0.325, 0.350, 0.375, 0.40, 0.425, 0.450, 0.475, 0.50, 0.525, 0.550, 0.575, 0.60, 0.625, 0.650, 0.675, 0.70, 0.725, 0.750, 0.775, 0.80, 0.825, 0.850, 0.875, 0.90, 0.925, 0.950, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.50, 2.75, 3.0, 3.25, 3.5, 3.75, or 4.0%; and the balance Fe. For example, one embodiment of the substantially cylindrical metal primer insert may include any amount in the range of 2-16% Ni; 10-20% Cr; 0-5% Mo; 0-0.6% C; 0-6.0% Cu; 0-0.5% Nb+Ta; 0-4.0% Mn; 0-2.0% Si and the balance Fe. One embodiment of the substantially cylindrical metal primer insert may include any amount in the range of 2-6% Ni; 13.5-19.5% Cr; 0-0.10% C; 1-7.0% Cu; 0.05-0.65% Nb+Ta; 0-3.0% Mn; 0-3.0% Si and the balance Fe. One embodiment of the substantially cylindrical metal primer insert may include any amount in the range of 3-5% Ni; 15.5-17.5% Cr; 0-0.07% C; 3-5.0% Cu; 0.15-0.45% Nb+Ta; 0-1.0% Mn; 0-1.0% Si and the balance Fe. One embodiment of the substantially cylindrical metal primer insert may include any amount in the range of 10-14% Ni; 16-18% Cr; 2-3% Mo; 0-0.03% C; 0-2% Mn; 0-1% Si and the balance Fe. One embodiment of the substantially cylindrical metal primer insert may include any amount in the range of 12-14% Cr; 0.15-0.4% C; 0-1% Mn; 0-1% Si and the balance Fe. One embodiment of the substantially cylindrical metal primer insert may include any amount in the range of 16-18% Cr; 0-0.05% C; 0-1% Mn; 0-1% Si and the balance Fe.

Titanium alloys that may be used in this invention include any alloy or modified alloy known to the skilled artisan including titanium grades 5-38 and more specifically titanium grades 5, 9, 18, 19, 20, 21, 23, 24, 25, 28, 29, 35, 36 or 38. Grades 5, 23, 24, 25, 29, 35, or 36 annealed or aged; Grades 9, 18, 28, or 38 cold-worked and stress-relieved or annealed; Grades 9, 18, 23, 28, or 29 transformed-beta condition; and Grades 19, 20, or 21 solution-treated or solution-treated and aged. Grade 5, also known as Ti6Al4V, Ti-6Al-4V or Ti 6-4, is the most commonly used alloy. It has a chemical composition of 6% aluminum, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen, and the remainder titanium. It is significantly stronger than commercially pure titanium while having the same stiffness and thermal properties (excluding thermal conductivity, which is about 60% lower in Grade 5 Ti than in CP Ti); Grade 6 contains 5% aluminium and 2.5% tin. It is also known as Ti-5Al-2.5Sn. This alloy has good weldability, stability and strength at elevated temperatures; Grade 7 and 7H contains 0.12 to 0.25% palladium. This grade is similar to Grade 2. The small quantity of palladium added gives it enhanced crevice corrosion resistance at low temperatures and high pH; Grade 9 contains 3.0% aluminium and 2.5% vanadium. This grade is a compromise between the ease of welding and manufacturing of the “pure” grades and the high strength of Grade 5; Grade 11 contains 0.12 to 0.25% palladium; Grade 12 contains 0.3% molybdenum and 0.8% nickel; Grades 13, 14, and 15 all contain 0.5% nickel and 0.05% ruthenium; Grade 16 contains 0.04 to 0.08% palladium; Grade 16H contains 0.04 to 0.08% palladium; Grade 17 contains 0.04 to 0.08% palladium; Grade 18 contains 3% aluminum, 2.5% vanadium and 0.04 to 0.08% palladium; Grade 19 contains 3% aluminum, 8% vanadium, 6% chromium, 4% zirconium, and 4% molybdenum; Grade 20 contains 3% aluminum, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum and 0.04% to 0.08% palladium; Grade 21 contains 15% molybdenum, 3% aluminum, 2.7% niobium, and 0.25% silicon; Grade 23 contains 6% aluminum, 4% vanadium, 0.13% (maximum) Oxygen; Grade 24 contains 6% aluminum, 4% vanadium and 0.04% to 0.08% palladium. Grade 25 contains 6% aluminum, 4% vanadium and 0.3% to 0.8% nickel and 0.04% to 0.08% palladium; Grades 26, 26H, and 27 all contain 0.08 to 0.14% ruthenium; Grade 28 contains 3% aluminum, 2.5% vanadium and 0.08 to 0.14% ruthenium; Grade 29 contains 6% aluminum, 4% vanadium and 0.08 to 0.14% ruthenium; Grades 30 and 31 contain 0.3% cobalt and 0.05% palladium; Grade 32 contains 5% aluminum, 1% tin, 1% zirconium, 1% vanadium, and 0.8% molybdenum; Grades 33 and 34 contain 0.4% nickel, 0.015% palladium, 0.025% ruthenium, and 0.15% chromium; Grade 35 contains 4.5% aluminum, 2% molybdenum, 1.6% vanadium, 0.5% iron, and 0.3% silicon; Grade 36 contains 45% niobium; Grade 37 contains 1.5% aluminum; and Grade 38 contains 4% aluminum, 2.5% vanadium, and 1.5% iron. Its mechanical properties are very similar to Grade 5, but has good cold workability similar to grade 9. One embodiment includes a Ti6Al4V composition. One embodiment includes a composition having 3-12% aluminum, 2-8% vanadium, 0.1-0.75% iron, 0.1-0.5% oxygen, and the remainder titanium. More specifically, about 6% aluminum, about 4% vanadium, about 0.25% iron, about 0.2% oxygen, and the remainder titanium. For example, one Ti composition may include 10 to 35% Cr, 0.05 to 15% Al, 0.05 to 2% Ti, 0.05 to 2% Y2O5, with the balance being either Fe, Ni or Co, or an alloy consisting of 20±1.0% Cr, 4.5±0.5% Al, 0.5±0.1% Y2O5 or ThO2, with the balance being Fe. For example, one Ti composition may include 15.0-23.0% Cr, 0.5-2.0% Si, 0.0-4.0% Mo, 0.0-1.2% Nb, 0.0-3.0% Fe, 0.0-0.5% Ti, 0.0-0.5% Al, 0.0-0.3% Mn, 0.0-0.1% Zr, 0.0-0.035% Ce, 0.005-0.025% Mg, 0.0005-0.005% B, 0.005-0.3% C, 0.0-20.0% Co, balance Ni. Sample Ti-based feedstock component includes 0-45% metal powder; 15-40% binder; 0-10% Polymer (e.g., thermoplastics and thermosets); surfactant 0-3%; lubricant 0-3%; sintering aid 0-1%. Another sample Ti-based feedstock component includes about 62% TiH2 powder as a metal powder; about 29% naphthalene as a binder; about 2.1-2.3% polymer (e.g., EVA/epoxy); about 2.3% SURFONIC N-100 ® as a Surfactant; lubricant is 1.5% stearic acid as a; about 0.4% silver as a sintering Aid. Examples of metal compounds include metal hydrides, such as TiH2, and intermetallics, such as TiAl and TiAl3. A specific instance of an alloy includes Ti-6Al,4V, among others. In another embodiment, the metal powder comprises at least approximately 45% of the volume of the feedstock, while in still another, it comprises between approximately 54.6% and 70.0%. In addition, Ti—Al alloys may consists essentially of 32-38% of Al and the balance of Ti and contains 0.005-0.20% of B, and the alloy which essentially consists of the above quantities of Al and Ti and contains, in addition to the above quantity of B, up to 0.2% of C, up to 0.3% of 0 and/or up to 0.3% of N (provided that 0+N add up to 0.4%) and c) 0.05-3.0% of Ni and/or 0.05-3.0% of Si, and the balance of Ti.

Parts are molded until they feel that the cavity has been filled. Both mold design factors such as runner and gate size, gate placement, venting and molding parameters set on the molding machine affect the molded part. A helium Pycnometer can determine if there are voids trapped inside the parts. During molding, you have a tool that can be used to measure the percent of theoretical density achieved on the “Green” or molded part. By crushing the measured “green” molded part back to powder, you can now confirm the percent of air (or voids) trapped in the molded part. To measure this, the density of the molded part should be measured in the helium Pycnometer and compared to the theoretical density of the feedstock. Then, take the same molded part that was used in the density test and crush it back to powder. If this granulate shows a density of more than 100% of that of the feedstock, then some of the primary binders have been lost during the molding process. The molding process needs to be corrected because using this process with a degraded feedstock will result in a larger shrinkage and result in a part smaller than that desired. It is vital to be sure that your molded parts are completely filled before continuing the manufacturing process for debinding and sintering. The helium Pycnometer provides this assurance. Primary debinding properly debound parts are extremely important to establish the correct sintering profile. The primary binder must be completely removed before attempting to start to remove the secondary binder as the secondary binder will travel through the pores created by the extraction of the primary binder. Primary debinding techniques depend on the feedstock type used to make the parts. However the feedstock supplier knows the amount of primary binders that have been added and should be removed before proceeding to the next process step. The feedstock supplier provides a minimum “brown density” that must be achieved before the parts can be moved into a furnace for final debinding and sintering. This minimum brown density will take into account that a small amount of the primary binder remnant may be present and could be removed by a suitable hold during secondary debinding and sintering. The sintering profile should be adjusted to remove the remaining small percent of primary binder before the removal of the secondary binder. Most external feedstock manufacturers provide only a weight loss percent that should be obtained to define suitable debinding. Solvent debound parts must be thoroughly dried, before the helium Pycnometer is used to determine the “brown” density so that the remnant solvent in the part does not affect the measured density value. When the feedstock manufacturer gives you the theoretical density of the “brown” or debound part, can validate the percent of debinding that has been achieved. Most Metal Injection Molding (MIM) operations today perform the secondary debinding and sintering in the same operation. Every MIM molder has gates and runners left over from molding their parts. So, you will be able to now re-use your gates and runners with confidence that they will shrink correctly after sintering. If the feedstock producers have given you the actual and theoretical densities of their feedstock, you can easily measure the densities of the gates and runners and compare the results to the values supplied. Once the regrind densities are higher than that required to maintain the part dimensions, the regrinds are no longer reusable.

Feedstock in accordance with the present invention may be prepared by blending the powdered metal with the binder and heating the blend to form a slurry. Uniform dispersion of the powdered metal in the slurry may be achieved by employing high shear mixing. The slurry may then be cooled to ambient temperature and then granulated to provide the feedstock for the metal injection molding.

The amount of powdered metal and binder in the feedstock may be selected to optimize moldability while insuring acceptable green densities. In one embodiment, the feedstock used for the metal injection molding portion of the invention may include at least about 40 percent by weight powdered metal, in another about 50 percent by weight powdered metal or more. In one embodiment, the feedstock includes at least about 60 percent by weight powdered metal, preferably about 65 percent by weight or more powdered metal. In yet another embodiment, the feedstock includes at least about 75 percent by weight powdered metal. In yet another embodiment, the feedstock includes at least about 80 percent by weight powdered metal. In yet another embodiment, the feedstock includes at least about 85 percent by weight powdered metal. In yet another embodiment, the feedstock includes at least about 90 percent by weight powdered metal.

The binding agent may be any suitable binding agent that does not destroy or interfere with the powdered metals. The binder may be present in an amount of about 50 percent or less by weight of the feedstock. In one embodiment, the binder is present in an amount ranging from 10 percent to about 50 percent by weight. In another embodiment, the binder is present in an amount of about 25 percent to about 50 percent by weight of the feedstock. In another embodiment, the binder is present in an amount of about 30 percent to about 40 percent by weight of the feedstock. In one embodiment, the binder is an aqueous binder. In another embodiment, the binder is an organic-based binder. Examples of binders include, but are not limited to, thermoplastic resins, waxes, and combinations thereof. Non-limiting examples of thermoplastic resins include polyolefins such as acrylic polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene carbonate, polyethylene glycol, and mixtures thereof. Suitable waxes include, but are not limited to, microcrystalline wax, bee wax, synthetic wax, and combinations thereof.

Examples of suitable powdered metals for use in the feedstock include, but are not limited to: stainless steel including martensitic and austenitic stainless steel, steel alloys, tungsten alloys, soft magnetic alloys such as iron, iron-silicon, electrical steel, iron-nickel (50Ni-50F3), low thermal expansion alloys, or combinations thereof. In one embodiment, the powdered metal is a mixture of stainless steel, brass and tungsten alloy. The stainless steel used in the present invention may be any 1 series carbon steels, 2 series nickel steels, 3 series nickel-chromium steels, 4 series molybdenum steels, series chromium steels, 6 series chromium-vanadium steels, 7 series tungsten steels, 8 series nickel-chromium-molybdenum steels, or 9 series silicon-manganese steels, e.g., 102, 174, 201, 202, 300, 302, 303, 304, 308, 309, 316, 316L, 316Ti, 321, 405, 408, 409, 410, 416, 420, 430, 439, 440, 446 or 601-665 grade stainless steel.

As known to those of ordinary skill in the art, stainless steel is an alloy of iron and at least one other component that imparts corrosion resistance. As such, in one embodiment, the stainless steel is an alloy of iron and at least one of chromium, nickel, silicon, molybdenum, or mixtures thereof. Examples of such alloys include, but are not limited to, an alloy containing about 1.5 to about 2.5 percent nickel, no more than about 0.5 percent molybdenum, no more than about 0.15 percent carbon, and the balance iron with a density ranging from about 7 g/cm³ to about 8 g/cm³; an alloy containing about 6 to about 8 percent nickel, no more than about 0.5 percent molybdenum, no more than about 0.15 percent carbon, and the balance iron with a density ranging from about 7 g/cm³ to about 8 g/cm³; an alloy containing about 0.5 to about 1 percent chromium, about 0.5 percent to about 1 percent nickel, no more than about 0.5 percent molybdenum, no more than about 0.2 percent carbon, and the balance iron with a density ranging from about 7 g/cm³ to about 8 g/cm³; an alloy containing about 2 to about 3 percent nickel, no more than about 0.5 percent molybdenum, about 0.3 to about 0.6 percent carbon, and the balance iron with a density ranging from about 7 g/cm³ to about 8 g/cm³; an alloy containing about 6 to about 8 percent nickel, no more than about 0.5 percent molybdenum, about 0.2 to about 0.5 percent carbon, and the balance iron with a density ranging from about 7 g/cm³ to about 8 g/cm³; an alloy containing about 1 to about 1.6 percent chromium, about 0.5 percent or less nickel, no more than about 0.5 percent molybdenum, about 0.9 to about 1.2 percent carbon, and the balance iron with a density ranging from about 7 g/cm³ to about 8 g/cm³; and combinations thereof.

Suitable tungsten alloys include an alloy containing about 2.5 to about 3.5 percent nickel, about 0.5 percent to about 2.5 percent copper or iron, and the balance tungsten with a density ranging from about 17.5 g/cm³ to about 18.5 g/cm³; about 3 to about 4 percent nickel, about 94 percent tungsten, and the balance copper or iron with a density ranging from about 17.5 g/cm³ to about 18.5 g/cm³; and mixtures thereof.

In addition, the binders may contain additives such as antioxidants, coupling agents, surfactants, elasticizing agents, dispersants, and lubricants as disclosed in U.S. Pat. No. 5,950,063, which is hereby incorporated by reference in its entirety. Suitable examples of antioxidants include, but are not limited to thermal stabilizers, metal deactivators, or combinations thereof. In one embodiment, the binder includes about 0.1 to about 2.5 percent by weight of the binder of an antioxidant. Coupling agents may include but are not limited to titanate, aluminate, silane, or combinations thereof. Typical levels range between 0.5 and 15% by weight of the binder.

The polymeric and composite casing components may be injection molded. Polymeric materials for the bullet-end and middle body components must have propellant compatibility and resistance to gun cleaning solvents and grease, as well as resistance to chemical, biological and radiological agents. The polymeric materials must have a temperature resistance higher than the cook-off temperature of the propellant, typically about 320° F. The polymeric materials must have elongation-to-break values that to resist deformation under interior ballistic pressure as high as 60,000 psi in all environments (temperatures from about −65 to about 320° F. and humidity from 0 to 100% relative humidity). According to one embodiment, the middle body component is either molded onto or snap-fit to the casing head-end component after which the bullet-end component is snap-fit or interference fit to the middle body component. The components may be formed from high-strength polymer, composite or ceramic.

Examples of suitable high strength polymers include composite polymer material including a tungsten metal powder, nylon 6/6, nylon 6, and glass fibers; and a specific gravity in a range of 3-10. The tungsten metal powder may be 50%-96% of a weight of the bullet body. The polymer material also includes about 0.5-15%, preferably about 1-12%, and most preferably about 2-9% by weight, of nylon 6/6, about 0.5-15%, preferably about 1-12%, and most preferably about 2-9% by weight, of nylon 6, and about 0.5-15%, preferably about 1-12%, and most preferably about 2-9% by weight, of glass fibers. It is most suitable that each of these ingredients be included in amounts less than 10% by weight. The cartridge casing body may be made of a modified ZYTEL® resin, available from E.I. DuPont De Nemours Co., a modified 612 nylon resin, modified to increase elastic response.

Examples of suitable polymers include polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, or urethane hybrids. Examples of suitable polymers also include aliphatic or aromatic polyamide, polyeitherimide, polysulfone, polyphenylsulfone, poly-phenylene oxide, liquid crystalline polymer and polyketone. Examples of suitable composites include polymers such as polyphenylsulfone reinforced with between about 30 and about 70 weight percent, and preferably up to about 65 weight percent of one or more reinforcing materials selected from glass fiber, ceramic fiber, carbon fiber, mineral fillers, organo nanoclay, or carbon nanotube. Preferred reinforcing materials, such as chopped surface-treated E-glass fibers provide flow characteristics at the above-described loadings comparable to unfilled polymers to provide a desirable combination of strength and flow characteristics that permit the molding of head-end components. Composite components can be formed by machining or injection molding. Finally, the cartridge case must retain sufficient joint strength at cook-off temperatures. More specifically, polymers suitable for molding of the projectile-end component have one or more of the following properties: Yield or tensile strength at −65° F.>10,000 psi Elongation-to-break at −65° F.>15% Yield or tensile strength at 73° F.>8,000 psi Elongation-to-break at 73° F.>50% Yield or tensile strength at 320° F.>4,000 psi Elongation-to-break at 320° F.>80%. Polymers suitable for molding of the middle-body component have one or more of the following properties: Yield or tensile strength at −65° F.>10,000 psi Yield or tensile strength at 73° F.>8,000 psi Yield or tensile strength at 320° F.>4,000 psi.

Commercially available polymers suitable for use in the present invention thus include polyphenylsulfones; copolymers of polyphenylsulfones with polyether-sulfones or polysulfones; copolymers and blends of polyphenylsulfones with polysiloxanes; poly(etherimide-siloxane); copolymers and blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly(etherimide-siloxane) copolymers; and the like. Particularly preferred are polyphenylsulfones and their copolymers with poly-sulfones or polysiloxane that have high tensile strength and elongation-to-break to sustain the deformation under high interior ballistic pressure. Such polymers are commercially available, for example, RADEL® R5800 polyphenylesulfone from Solvay Advanced Polymers. The polymer can be formulated with up to about 10 wt % of one or more additives selected from internal mold release agents, heat stabilizers, anti-static agents, colorants, impact modifiers and UV stabilizers.

The polymers of the present invention can also be used for conventional two-piece metal-plastic hybrid cartridge case designs and conventional shotgun shell designs. One example of such a design is an ammunition cartridge with a one-piece substantially cylindrical polymeric cartridge casing body with an open projectile-end and an end opposing the projectile-end with a male or female coupling element; and a cylindrical metal cartridge casing head-end component with an essentially closed base end with a primer hole opposite an open end having a coupling element that is a mate for the coupling element on the opposing end of the polymeric cartridge casing body joining the open end of the head-end component to the opposing end of the polymeric cartridge casing body. The high polymer ductility permits the casing to resist breakage.

One embodiment includes a 2 cavity prototype mold having an upper portion and a base portion for a 5.56 case having a metal insert over-molded with a Nylon 6 (polymer) based material. In this embodiment the polymer in the base includes a lip or flange to extract the case from the weapon. One 2-cavity prototype mold to produce the upper portion of the 5.56 case can be made using a stripper plate tool using an Osco hot spur and two subgates per cavity. Another embodiment includes a subsonic version, the difference from the standard and the subsonic version is the walls are thicker thus requiring less powder. This will decrease the velocity of the bullet thus creating a subsonic round.

The extracting inserts is used to give the polymer case a tough enough ridge and groove for the weapons extractor to grab and pull the case out the chamber of the gun. The extracting insert is made of 17-4 stainless steel that is hardened to 42-45 rc. The insert may be made of aluminum, brass, cooper, steel or even an engineered resin with enough tensile strength.

The insert is over molded in an injection molded process using a nano clay particle filled Nylon material. The inserts can be machined or stamped. In addition, an engineered resin able to withstand the demand on the insert allows injection molded and/or even transfer molded.

One of ordinary skill in the art will know that many propellant types and weights can be used to prepare workable ammunition and that such loads may be determined by a careful trial including initial low quantity loading of a given propellant and the well known stepwise increasing of a given propellant loading until a maximum acceptable load is achieved. Extreme care and caution is advised in evaluating new loads. The propellants available have various burn rates and must be carefully chosen so that a safe load is devised.

The components may be made of polymeric compositions, metals, ceramics, alloys, or combinations and mixtures thereof. In addition, the components may be mixed and matched with one or more components being made of different materials. For example, the middle body component (not shown) may be polymeric; the bullet-end component 18 may be polymeric; and a substantially cylindrical insert (not shown) may be metal. Similarly, the middle body component (not shown) may be polymeric; the bullet-end component 18 may be metal; and a substantially cylindrical insert (not shown) may be an alloy. The middle body component (not shown) may be polymeric; the bullet-end component 18 may be an alloy; and a substantially cylindrical insert (not shown) may be an alloy. The middle body component (not shown); the bullet-end component 18; and/or the substantially cylindrical insert may be made of a metal that is formed by a metal injection molding process.

FIG. 14 depicts an exploded view of the polymeric cartridge casing. A cartridge 10 suitable for use with high velocity rifles is shown manufactured with a middle body component 28 having a substantially cylindrical open-ended polymeric bullet-end 18 extending from forward end opening 16 rearward to opposite end 20. A portion of a cartridge suitable for use with high velocity rifles is shown manufactured with a polymer casing 12 showing a powder chamber 14. The polymer casing 12 has a substantially cylindrical opposite end 20. The bullet-end component 18 may be formed with the coupling end 22 formed on end 20. The coupling end 22 is shown as a female element, but may also be configured as a male element in alternate embodiments of the invention. The middle body component 28 is connected to a substantially cylindrical coupling element 30 of the substantially cylindrical insert 32. The substantially cylindrical open-ended polymeric bullet-end 18 has a shoulder 24 forming chamber neck 26 and a bullet 56 inserted therein. The substantially cylindrical insert 32 also has a flange 46 cut therein and a primer recess (not shown) formed therein for ease of insertion of the primer (not shown). When contacted the coupling end 22 interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip 44 to form a physical interlock between substantially cylindrical insert 32 and middle body component 28. In one embodiment of the present invention, the substantially cylindrical insert 32 may be made of a metal that is formed by a metal injection molding process. The model design may be seen herein.

The molded substantially cylindrical insert 32 is then bound to the middle body component 28. In the metal injection molding process of making the substantially cylindrical insert 32 a mold is made in the shape of the substantially cylindrical insert 32 including the desired profile of the primer recess (not shown). The substantially cylindrical insert 32 includes a substantially cylindrical coupling element 30 extending from a bottom surface 34 that is opposite a top surface (not shown). Located in the top surface (not shown) is a primer recess (not shown) that extends toward the bottom surface 34. A primer flash hole (not shown). is located in the substantially cylindrical insert 32 and extends through the bottom surface 34 into the powder chamber 14. The coupling end (not shown) extends through the primer flash hole (not shown) to form an aperture coating (not shown) while retaining a passage from the top surface (not shown) through the bottom surface (not shown) and into the powder chamber 14 to provides support and protection about the primer flash hole (not shown). When contacted the coupling end (not shown) interlocks with the substantially cylindrical coupling element 30, through the coupling element 30 that extends with a taper to a smaller diameter at the tip (not shown) to form a physical interlock between substantially cylindrical insert 32 and middle body component 28.

For example, the metal injection molding process, which generally involves mixing fine metal powders with binders to form a feedstock that is injection molded into a closed mold, may be used to form a substantially cylindrical insert. After ejection from the mold, the binders are chemically or thermally removed from the substantially cylindrical insert so that the part can be sintered to high density. During the sintering process, the individual metal particles metallurgically bond together as material diffusion occurs to remove most of the porosity left by the removal of the binder.

The raw materials for metal injection molding are metal powders and a thermoplastic binder. There are at least two Binders included in the blend, a primary binder and a secondary binder. This blended powder mix is worked into the plasticized binder at elevated temperature in a kneader or shear roll extruder. The intermediate product is the so-called feedstock. It is usually granulated with granule sizes of several millimeters. In metal injection molding, only the binders are heated up, and that is how the metal is carried into the mold cavity whereas,

FIGS. 15A and 15B depict a view of the substantially cylindrical open-ended polymeric bullet-end having a shoulder forming chamber neck and a bullet. FIGS. 15A and 15B depict show the substantially cylindrical open-ended polymeric bullet-end 18 has a shoulder 24 forming chamber neck 26 and a bullet (not shown). One embodiment includes modifications to strengthen the neck of the mouth 60 and to the internal base area 62 to reduce nose tearing and lodging in the chamber. The substantially cylindrical open-ended polymeric bullet-end 18 illustrates a lock 58 (e.g., 0.030×0.003) and added a step to allow for the lock 58 to flex out during firing. The polymer was added to the external area to strengthen the neck of the mouth 60 and to the internal base area 62. The interference of the bullet to the neck was increased by adding the polymer to the inside of the neck 64 and the exit lock modified by adding an angle to the rim 66.

FIG. 16 depicts an elevation view of a bullet-end component of the polymeric cartridge casing. A cartridge (not shown) suitable for use with high velocity rifles may be manufactured as a modular component system with a middle body component (not shown) with one end being connected to a bullet-end component 18 that is connected to a bullet (not shown) inserted therein and the other end being connected to a substantially cylindrical insert (not shown). As the cartridge (not shown) is made as a modular component system it must be assembled and fused together, e.g., the substantially cylindrical insert (not shown) must be attached to the middle body component (not shown) and the bullet-end component 18 must also be attached to the middle body component (not shown). In addition, the bullet (not shown) must be attached to the bullet-end component 18 at the forward end opening 16. The bullet-end component 18 has a shoulder 24 forming chamber neck 26 and a forward end opening 16 at one end to receive a bullet (not shown) and a powder chamber coupling 68 at the other that mates to the powder chamber (not shown). The forward end opening 16 may include a textured surface 70 that extends into the inner neck 64 to enhance the sealing of the bullet (not shown) and the bullet-end component 18. The textured surface 70 may be in the form of groves, slots, channels, scratches or any other texture to increase the surface area to enhance bonding of the bullet (not shown) and the bullet-end component 18. For example, the forward end opening 16 may include a textured surface 70 of channels that extend into the inner neck 64 to enhance the sealing of the bullet (not shown) and the bullet-end component 18. During assembly the textured surface 70 provides additional surface area for the adhesive to interact with and thus secure the seal between the bullet (not shown) and the forward end opening 16.

FIG. 17 depicts a side, cross-sectional view of a bullet-end component of the polymeric cartridge casing. A cartridge (not shown) suitable for use with high velocity rifles may be manufactured as a modular component system with a middle body component (not shown) with one end being connected to a bullet-end component 18 that is connected to a bullet (not shown) inserted therein and the other end being connected to a substantially cylindrical insert (not shown). The cartridge (not shown) is made as a modular component system it must be assembled and fused together, e.g., the substantially cylindrical insert (not shown) must be attached to the middle body component (not shown) and the bullet-end component 18 must also be attached to the middle body component (not shown). In addition, the bullet (not shown) must be attached to the bullet-end component 18 at the forward end opening 16. The bullet-end component 18 has a shoulder 24 forming chamber neck 26 and a forward end opening 16 at one end to receive a bullet (not shown) and a powder chamber coupling 68 at the other that mates to the powder chamber (not shown). The forward end opening 16 may include a textured surface 70 that extends into the inner neck 64 to enhance the sealing of the bullet (not shown) and the bullet-end component 18. The textured surface 70 may be in the form of groves, slots, channels, scratches or any other texture to increase the surface area to enhance bonding of the bullet (not shown) and the bullet-end component 18. For example, the forward end opening 16 may include a textured surface 70 of channels or grooves that extend into the inner neck 64 to enhance the sealing of the bullet (not shown) and the bullet-end component 18. During assembly the textured surface 70 provides additional surface area for the adhesive to interact with and thus secure the seal between the bullet (not shown) and the forward end opening 16. For example the textured surface 70 may be grooves that extend into the inner neck 64 so that an adhesive when applied to the bullet can wick into the grooves and into the inner neck 64 to provide a contact area on the bullet and the inner neck 64 for the adhesive. The adhesive can then be cured (e.g., UV light) and sealed. The textured surface 70 may be in any form that allows wicking and/or the increasing of the surface area, e.g., hatching, grooves, scratches, roughness, etc.

The description of the preferred embodiments should be taken as illustrating, rather than as limiting, the present invention as defined by the claims. As will be readily appreciated, numerous combinations of the features set forth above can be utilized without departing from the present invention as set forth in the claims. Such variations are not regarded as a departure from the spirit and scope of the invention, and all such modifications are intended to be included within the scope of the following claims.

It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method, kit, reagent, or composition of the invention, and vice versa. Furthermore, compositions of the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention can be employed in various embodiments without departing from the scope of the invention. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specification are indicative of the level of skill of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

The term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations that contain repeats ofone or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims. 

What is claimed is:
 1. A method of making a polymer ammunition cartridge having an injection molded primer insert comprising by the steps of: providing a primer insert injection mold, wherein the primer insert comprises a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash aperture positioned in the primer recess to extend through the bottom surface, a flash hole groove that extends circumferentially about the primer flash aperture in the primer recess; and a flange that extends circumferentially about an outer edge of the top surface; molding a primer insert by adding an injection molding composition to the primer insert injection mold to form the primer insert; molding from a first polymer composition a substantially cylindrical polymeric middle body over primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the primer insert to the flange and extends over an interior surface of the substantially cylindrical coupling region into the primer flash hole aperture to the flash hole groove, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region through the primer flash hole aperture to the flash hole groove; forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region; and coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture.
 2. The method of claim 1, wherein the first polymer composition is the same as the second polymer composition.
 3. The method of claim 1, wherein the first polymer composition is a ductile polymer.
 4. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise a nylon polymer.
 5. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise a fiber-reinforced polymeric composite.
 6. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise between about 10 and about 70 wt % glass fiber fillers, mineral fillers, or mixtures thereof.
 7. The method of claim 1, wherein the bullet aperture comprises one or more cannelures formed on an inner circumferential surface of the bullet aperture.
 8. The method of claim 1, wherein the substantially cylindrical coupling region and the polymeric bullet-end coupling are welded or bonded together.
 9. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly(etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly(etherimide-siloxane) copolymers.
 10. The method of claim 1, further comprising a neck positioned between the bullet aperture and the polymeric bullet-end coupling.
 11. The method of claim 10, further comprising one or more internal structures in the neck to support a bullet.
 12. The method of claim 1, wherein the bullet aperture comprises one, two, three, or more annular rings that mate with one, two, three, or more corresponding annular grooves positioned on the bullet.
 13. The method of claim 1, wherein the primer insert is a metal primer insert comprising 16-18% Cr; 0-0.05% C; 0-1% Mn; 0-1% Si and the balance Fe.
 14. The method of claim 1, wherein the primer insert is a metal primer insert comprising 2-16% Ni; 10-20% Cr; 0-5% Mo; 0-0.6% C; 0-6.0% Cu; 0-0.5% Nb+Ta; 0-4.0% Mn; 0-2.0% Si and the balance Fe.
 15. The method of claim 1, wherein the primer insert is a metal primer insert comprising 2-6% Ni; 13.5-19.5% Cr; 0-0.10% C; 1-7.0% Cu; 0.05-0.65% Nb+Ta; 0-3.0% Mn; 0-3.0% Si and the balance Fe.
 16. The method of claim 1, wherein the primer insert is a metal primer insert comprising 3-5% Ni; 15.5-17.5% Cr; 0-0.07% C; 3-5.0% Cu; 0.15-0.45% Nb+Ta; 0-1.0% Mn; 0-1.0% Si and the balance Fe.
 17. The method of claim 1, wherein the primer insert is a metal primer insert comprising 10-14% Ni; 16-18% Cr; 2-3% Mo; 0-0.03% C; 0-2% Mn; 0-1% Si and the balance Fe.
 18. The method of claim 1, wherein the injection molding composition comprises powdered metal comprising 12-14% Cr; 0.15-0.4% C; 0-1% Mn; 0-1% Si and the balance Fe.
 19. The method of claim 1, wherein the injection molding composition comprises powdered metal comprising 3-12% aluminum, 2-8% vanadium, 0.1-0.75% iron, 0.1-0.5% oxygen, and the remainder titanium.
 20. The method of claim 1, wherein the injection molding composition comprises powdered metal comprising about 6% aluminum, about 4% vanadium, about 0.25% iron, about 0.2% oxygen, and the remainder titanium.
 21. The method of claim 1, wherein the injection molding composition comprises one or more metals.
 22. A method of making a polymer ammunition cartridge having an injection molded primer insert comprising by the steps of: forming a primer insert by injection molding from a primer insert injection mold, wherein the primer insert comprises a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash aperture positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface; providing a first polymer composition for molding a polymer ammunition cartridge; molding from the first polymer composition a substantially cylindrical polymeric middle body having the primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the primer insert to the flange and extends over an interior surface of the substantially cylindrical coupling region to the primer flash hole aperture, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region to the primer flash hole aperture; forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region, a neck positioned between the bullet aperture and the polymeric bullet-end coupling and one or more cannelures formed on an inner circumferential surface of the bullet aperture; and coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture. 